ITS/AliITSsimulationSPD.cxx

   1 #include <iostream.h>
   2 #include <TRandom.h>
   3 #include <TH1.h>
   4 #include <TMath.h>
   5 #include <TString.h>
   6 #include <TParticle.h>
   7
   8
   9 #include "AliRun.h"
  10 #include "AliITS.h"
  11 #include "AliITShit.h"
  12 #include "AliITSdigit.h"
  13 #include "AliITSmodule.h"
  14 #include "AliITSMapA2.h"
  15 #include "AliITSsimulationSPD.h"
  16 #include "AliITSsegmentation.h"
  17 #include "AliITSresponse.h"
  18
  19
  20
  21
  22 ClassImp(AliITSsimulationSPD)
  23 ////////////////////////////////////////////////////////////////////////
  24 // Version: 0
  25 // Written by Boris Batyunya
  26 // December 20 1999
  27 //
  28 // AliITSsimulationSPD is the simulation of SPDs
  29 //________________________________________________________________________
  30
  31
  32 AliITSsimulationSPD::AliITSsimulationSPD()
  33 {
  34   // constructor
  35   fResponse = 0;
  36   fSegmentation = 0;
  37   fMapA2=0;
  38   fHis = 0;
  39   fNoise=0.;
  40   fBaseline=0.;
  41   fNPixelsZ=0;
  42   fNPixelsX=0;
  43 }
  44
  45
  46 //_____________________________________________________________________________
  47
  48 AliITSsimulationSPD::AliITSsimulationSPD(AliITSsegmentation *seg, AliITSresponse *resp) {
  49   // standard constructor
  50
  51       fHis = 0;
  52       fResponse = resp;
  53       fSegmentation = seg;
  54
  55       fResponse->GetNoiseParam(fNoise,fBaseline);
  56
  57       fMapA2 = new AliITSMapA2(fSegmentation);
  58
  59       //
  60
  61       fNPixelsZ=fSegmentation->Npz();
  62       fNPixelsX=fSegmentation->Npx();
  63
  64 }
  65
  66 //_____________________________________________________________________________
  67
  68 AliITSsimulationSPD::~AliITSsimulationSPD() {
  69   // destructor
  70
  71   delete fMapA2;
  72
  73   if (fHis) {
  74      fHis->Delete();
  75      delete fHis;
  76   }
  77 }
  78
  79
  80 //__________________________________________________________________________
  81 AliITSsimulationSPD::AliITSsimulationSPD(const AliITSsimulationSPD &source){
  82   //     Copy Constructor
  83   if(&source == this) return;
  84   this->fMapA2 = source.fMapA2;
  85   this->fNoise = source.fNoise;
  86   this->fBaseline = source.fBaseline;
  87   this->fNPixelsX = source.fNPixelsX;
  88   this->fNPixelsZ = source.fNPixelsZ;
  89   this->fHis = source.fHis;
  90   return;
  91 }
  92
  93 //_________________________________________________________________________
  94 AliITSsimulationSPD&
  95   AliITSsimulationSPD::operator=(const AliITSsimulationSPD &source) {
  96   //    Assignment operator
  97   if(&source == this) return *this;
  98   this->fMapA2 = source.fMapA2;
  99   this->fNoise = source.fNoise;
 100   this->fBaseline = source.fBaseline;
 101   this->fNPixelsX = source.fNPixelsX;
 102   this->fNPixelsZ = source.fNPixelsZ;
 103   this->fHis = source.fHis;
 104   return *this;
 105   }
 106 //_____________________________________________________________________________
 107
 108 void AliITSsimulationSPD::DigitiseModule(AliITSmodule *mod, Int_t module, Int_t dummy)
 109 {
 110   // digitize module
 111
 112     const Float_t kEnToEl = 2.778e+8; // GeV->charge in electrons
 113                                       // for 3.6 eV/pair
 114     const Float_t kconv = 10000.;     // cm -> microns
 115
 116     Float_t spdLength = fSegmentation->Dz();
 117     Float_t spdWidth = fSegmentation->Dx();
 118
 119     Float_t difCoef, dum;
 120     fResponse->DiffCoeff(difCoef,dum);
 121
 122     Float_t zPix0 = 1e+6;
 123     Float_t xPix0 = 1e+6;
 124     Float_t yPrev = 1e+6;
 125
 126     Float_t zPitch = fSegmentation->Dpz(0);
 127     Float_t xPitch = fSegmentation->Dpx(0);
 128
 129     TObjArray *fHits = mod->GetHits();
 130     Int_t nhits = fHits->GetEntriesFast();
 131     if (!nhits) return;
 132
 133     //cout<<"len,wid,dy,nx,nz,pitchx,pitchz ="<<spdLength<<","<<spdWidth<<","<<fSegmentation->Dy()<<","<<fNPixelsX<<","<<fNPixelsZ<<","<<xPitch<<","<<zPitch<<endl;
 134   //  Array of pointers to the label-signal list
 135
 136     Int_t maxNDigits = fNPixelsX*fNPixelsZ + fNPixelsX ;;
 137     Float_t  **pList = new Float_t* [maxNDigits];
 138     memset(pList,0,sizeof(Float_t*)*maxNDigits);
 139     Int_t indexRange[4] = {0,0,0,0};
 140
 141     // Fill detector maps with GEANT hits
 142     // loop over hits in the module
 143     static Bool_t first;
 144     Int_t lasttrack=-2;
 145     Int_t hit, iZi, jz, jx;
 146     //cout<<"SPD: module,nhits ="<<module<<","<<nhits<<endl;
 147     Int_t idhit=-1;
 148     for (hit=0;hit<nhits;hit++) {
 149         AliITShit *iHit = (AliITShit*) fHits->At(hit);
 150         Int_t layer = iHit->GetLayer();
 151         Float_t yPix0 = -73;
 152         if(layer == 1) yPix0 = -77;
 153
 154         if(iHit->StatusEntering()) idhit=hit;
 155         Int_t itrack = iHit->GetTrack();
 156         Int_t dray = 0;
 157
 158         if (lasttrack != itrack || hit==(nhits-1)) first = kTRUE;
 159
 160         //        Int_t parent = iHit->GetParticle()->GetFirstMother();
 161         Int_t partcode = iHit->GetParticle()->GetPdgCode();
 162
 163 //  partcode (pdgCode): 11 - e-, 13 - mu-, 22 - gamma, 111 - pi0, 211 - pi+
 164 //                      310 - K0s, 321 - K+, 2112 - n, 2212 - p, 3122 - lambda
 165
 166         /*
 167         Float_t px = iHit->GetPXL();   // the momenta at the
 168         Float_t py = iHit->GetPYL();   // each  GEANT step
 169         Float_t pz = iHit->GetPZL();
 170         Float_t ptot = 1000*sqrt(px*px+py*py+pz*pz);
 171         */
 172
 173         Float_t pmod = iHit->GetParticle()->P(); // total momentum at the
 174                                                    // vertex
 175         pmod *= 1000;
 176
 177
 178         if(partcode == 11 && pmod < 6) dray = 1; // delta ray is e-
 179                                                  // at p < 6 MeV/c
 180
 181
 182         //  Get hit z and x(r*phi) cordinates for each module (detector)
 183         //  in local system.
 184
 185         Float_t zPix = kconv*iHit->GetZL();
 186         Float_t xPix = kconv*iHit->GetXL();
 187         Float_t yPix = kconv*iHit->GetYL();
 188
 189         // Get track status
 190         Int_t status = iHit->GetTrackStatus();
 191         //cout<<"hit,status,y ="<<hit<<","<<status<<","<<yPix<<endl;
 192
 193         // Check boundaries
 194         if(zPix  > spdLength/2) {
 195           //cout<<"!!!1 z outside ="<<zPix<<endl;
 196          zPix = spdLength/2 - 10;
 197          //cout<<"!!!2 z outside ="<<zPix<<endl;
 198         }
 199         if(zPix  < 0 && zPix < -spdLength/2) {
 200           //cout<<"!!!1 z outside ="<<zPix<<endl;
 201          zPix = -spdLength/2 + 10;
 202          //cout<<"!!!2 z outside ="<<zPix<<endl;
 203         }
 204         if(xPix  > spdWidth/2) {
 205           //cout<<"!!!1 x outside ="<<xPix<<endl;
 206          xPix = spdWidth/2 - 10;
 207          //cout<<"!!!2 x outside ="<<xPix<<endl;
 208         }
 209         if(xPix  < 0 && xPix < -spdWidth/2) {
 210           //cout<<"!!!1 x outside ="<<xPix<<endl;
 211          xPix = -spdWidth/2 + 10;
 212          //cout<<"!!!2 x outside ="<<xPix<<endl;
 213         }
 214         Int_t trdown = 0;
 215
 216         // enter Si or after event in Si
 217         if (status == 66 ) {
 218            zPix0 = zPix;
 219            xPix0 = xPix;
 220            yPrev = yPix;
 221         }
 222
 223         Float_t depEnergy = iHit->GetIonization();
 224         // skip if the input point to Si
 225
 226         if(depEnergy <= 0.) continue;
 227
 228         // if track returns to the opposite direction:
 229         if (yPix < yPrev) {
 230             trdown = 1;
 231         }
 232
 233
 234         // take into account the holes diffusion inside the Silicon
 235         // the straight line between the entrance and exit points in Si is
 236         // divided into the several steps; the diffusion is considered
 237         // for each end point of step and charge
 238         // is distributed between the pixels through the diffusion.
 239
 240
 241         //  ---------- the diffusion in Z (beam) direction -------
 242
 243         Float_t charge = depEnergy*kEnToEl;         // charge in e-
 244         Float_t drPath = 0.;
 245         Float_t tang = 0.;
 246         Float_t sigmaDif = 0.;
 247         Float_t zdif = zPix - zPix0;
 248         Float_t xdif = xPix - xPix0;
 249         Float_t ydif = TMath::Abs(yPix - yPrev);
 250         Float_t ydif0 = TMath::Abs(yPrev - yPix0);
 251
 252         if(ydif < 1) continue; // ydif is not zero
 253
 254         Float_t projDif = sqrt(xdif*xdif + zdif*zdif);
 255
 256         Int_t ndZ = (Int_t)TMath::Abs(zdif/zPitch) + 1;
 257         Int_t ndX = (Int_t)TMath::Abs(xdif/xPitch) + 1;
 258
 259         // number of the steps along the track:
 260         Int_t nsteps = ndZ;
 261         if(ndX > ndZ) nsteps = ndX;
 262         if(nsteps < 6) nsteps = 6;  // minimum number of the steps
 263
 264         if (projDif < 5 ) {
 265            drPath = (yPix-yPix0)*1.e-4;
 266            drPath = TMath::Abs(drPath);        // drift path in cm
 267            sigmaDif = difCoef*sqrt(drPath);    // sigma diffusion in cm
 268            sigmaDif = sigmaDif*kconv;         // sigma diffusion in microns
 269            nsteps = 1;
 270         }
 271
 272         if(projDif > 5) tang = ydif/projDif;
 273         Float_t dCharge = charge/nsteps;       // charge in e- for one step
 274         Float_t dZ = zdif/nsteps;
 275         Float_t dX = xdif/nsteps;
 276
 277         for (iZi = 1;iZi <= nsteps;iZi++) {
 278             Float_t dZn = iZi*dZ;
 279             Float_t dXn = iZi*dX;
 280             Float_t zPixn = zPix0 + dZn;
 281             Float_t xPixn = xPix0 + dXn;
 282
 283             if(projDif >= 5) {
 284               Float_t dProjn = sqrt(dZn*dZn+dXn*dXn);
 285                 drPath = dProjn*tang*1.e-4; // drift path for iZi step in cm
 286               if(trdown == 0) {
 287                 drPath = TMath::Abs(drPath) + ydif0*1.e-4;
 288               }
 289               if(trdown == 1) {
 290                 drPath = ydif0*1.e-4 - TMath::Abs(drPath);
 291                 drPath = TMath::Abs(drPath);
 292               }
 293               sigmaDif = difCoef*sqrt(drPath);
 294               sigmaDif = sigmaDif*kconv;         // sigma diffusion in microns
 295             }
 296
 297             zPixn = (zPixn + spdLength/2.);
 298             xPixn = (xPixn + spdWidth/2.);
 299             Int_t nZpix, nXpix;
 300             fSegmentation->GetPadIxz(xPixn,zPixn,nXpix,nZpix);
 301             zPitch = fSegmentation->Dpz(nZpix);
 302             fSegmentation->GetPadTxz(xPixn,zPixn);
 303             // set the window for the integration
 304             Int_t jzmin = 1;
 305             Int_t jzmax = 3;
 306             if(nZpix == 1) jzmin =2;
 307             if(nZpix == fNPixelsZ) jzmax = 2;
 308
 309             Int_t jxmin = 1;
 310             Int_t jxmax = 3;
 311             if(nXpix == 1) jxmin =2;
 312             if(nXpix == fNPixelsX) jxmax = 2;
 313
 314             Float_t zpix = nZpix;
 315             Float_t dZright = zPitch*(zpix - zPixn);
 316             Float_t dZleft = zPitch - dZright;
 317
 318             Float_t xpix = nXpix;
 319             Float_t dXright = xPitch*(xpix - xPixn);
 320             Float_t dXleft = xPitch - dXright;
 321
 322             Float_t dZprev = 0.;
 323             Float_t dZnext = 0.;
 324             Float_t dXprev = 0.;
 325             Float_t dXnext = 0.;
 326
 327             for(jz=jzmin; jz <=jzmax; jz++) {
 328                 if(jz == 1) {
 329                   dZprev = -zPitch - dZleft;
 330                   dZnext = -dZleft;
 331                 }
 332                 if(jz == 2) {
 333                   dZprev = -dZleft;
 334                   dZnext = dZright;
 335                 }
 336                 if(jz == 3) {
 337                   dZprev = dZright;
 338                   dZnext = dZright + zPitch;
 339                 }
 340                 // kz changes from 1 to the fNofPixels(270)
 341                 Int_t kz = nZpix + jz -2;
 342
 343                 Float_t zArg1 = dZprev/sigmaDif;
 344                 Float_t zArg2 = dZnext/sigmaDif;
 345                 Float_t zProb1 = TMath::Erfc(zArg1);
 346                 Float_t zProb2 = TMath::Erfc(zArg2);
 347                 Float_t dZCharge =0.5*(zProb1-zProb2)*dCharge;
 348
 349
 350                 // ----------- holes diffusion in X(r*phi) direction  --------
 351
 352                 if(dZCharge > 1.) {
 353                   for(jx=jxmin; jx <=jxmax; jx++) {
 354                      if(jx == 1) {
 355                        dXprev = -xPitch - dXleft;
 356                        dXnext = -dXleft;
 357                      }
 358                      if(jx == 2) {
 359                        dXprev = -dXleft;
 360                        dXnext = dXright;
 361                      }
 362                      if(jx == 3) {
 363                        dXprev = dXright;
 364                        dXnext = dXright + xPitch;
 365                      }
 366                      Int_t kx = nXpix + jx -2;
 367
 368                      Float_t xArg1 = dXprev/sigmaDif;
 369                      Float_t xArg2 = dXnext/sigmaDif;
 370                      Float_t xProb1 = TMath::Erfc(xArg1);
 371                      Float_t xProb2 = TMath::Erfc(xArg2);
 372                      Float_t dXCharge =0.5*(xProb1-xProb2)*dZCharge;
 373
 374                      if(dXCharge > 1.) {
 375                        Int_t index = kz-1;
 376
 377                        if (first) {
 378                           indexRange[0]=indexRange[1]=index;
 379                           indexRange[2]=indexRange[3]=kx-1;
 380                           first=kFALSE;
 381                        }
 382
 383                        indexRange[0]=TMath::Min(indexRange[0],kz-1);
 384                        indexRange[1]=TMath::Max(indexRange[1],kz-1);
 385                        indexRange[2]=TMath::Min(indexRange[2],kx-1);
 386                        indexRange[3]=TMath::Max(indexRange[3],kx-1);
 387
 388                        // build the list of digits for this module
 389                        Double_t signal=fMapA2->GetSignal(index,kx-1);
 390                        signal+=dXCharge;
 391                        fMapA2->SetHit(index,kx-1,(double)signal);
 392                      }      // dXCharge > 1 e-
 393                   }       // jx loop
 394                 }       // dZCharge > 1 e-
 395             }        // jz loop
 396         }         // iZi loop
 397
 398         if (status == 65) {   // the step is inside of Si
 399            zPix0 = zPix;
 400            xPix0 = xPix;
 401         }
 402         yPrev = yPix;
 403
 404         if(dray == 0) {
 405             GetList(itrack,idhit,pList,indexRange);
 406         }
 407
 408         lasttrack=itrack;
 409     }   // hit loop inside the module
 410
 411
 412     // introduce the electronics effects and do zero-suppression
 413     ChargeToSignal(pList);
 414
 415     // clean memory
 416
 417     fMapA2->ClearMap();
 418
 419
 420 }
 421
 422 //---------------------------------------------
 423 void AliITSsimulationSPD::GetList(Int_t label,Int_t idhit,Float_t **pList,Int_t *indexRange)
 424 {
 425   // lop over nonzero digits
 426
 427
 428   //set protection
 429   for(int k=0;k<4;k++) {
 430      if (indexRange[k] < 0) indexRange[k]=0;
 431   }
 432
 433   for(Int_t iz=indexRange[0];iz<indexRange[1]+1;iz++){
 434     for(Int_t ix=indexRange[2];ix<indexRange[3]+1;ix++){
 435
 436         Float_t signal=fMapA2->GetSignal(iz,ix);
 437
 438         if (!signal) continue;
 439
 440         Int_t globalIndex = iz*fNPixelsX+ix; // GlobalIndex starts from 0!
 441         if(!pList[globalIndex]){
 442
 443            //
 444            // Create new list (9 elements - 3 signals and 3 tracks + 3 hits)
 445            //
 446
 447            pList[globalIndex] = new Float_t [9];
 448
 449            // set list to -3
 450
 451            *pList[globalIndex] = -3.;
 452            *(pList[globalIndex]+1) = -3.;
 453            *(pList[globalIndex]+2) = -3.;
 454            *(pList[globalIndex]+3) =  0.;
 455            *(pList[globalIndex]+4) =  0.;
 456            *(pList[globalIndex]+5) =  0.;
 457            *(pList[globalIndex]+6) = -1.;
 458            *(pList[globalIndex]+7) = -1.;
 459            *(pList[globalIndex]+8) = -1.;
 460
 461
 462            *pList[globalIndex] = (float)label;
 463            *(pList[globalIndex]+3) = signal;
 464            *(pList[globalIndex]+6) = (float)idhit;
 465         }
 466         else{
 467
 468           // check the signal magnitude
 469
 470           Float_t highest = *(pList[globalIndex]+3);
 471           Float_t middle = *(pList[globalIndex]+4);
 472           Float_t lowest = *(pList[globalIndex]+5);
 473
 474           signal -= (highest+middle+lowest);
 475
 476           //
 477           //  compare the new signal with already existing list
 478           //
 479
 480           if(signal<lowest) continue; // neglect this track
 481
 482           if (signal>highest){
 483             *(pList[globalIndex]+5) = middle;
 484             *(pList[globalIndex]+4) = highest;
 485             *(pList[globalIndex]+3) = signal;
 486
 487             *(pList[globalIndex]+2) = *(pList[globalIndex]+1);
 488             *(pList[globalIndex]+1) = *pList[globalIndex];
 489             *pList[globalIndex] = label;
 490
 491             *(pList[globalIndex]+8) = *(pList[globalIndex]+7);
 492             *(pList[globalIndex]+7) = *(pList[globalIndex]+6);
 493             *(pList[globalIndex]+6) = idhit;
 494           }
 495           else if (signal>middle){
 496             *(pList[globalIndex]+5) = middle;
 497             *(pList[globalIndex]+4) = signal;
 498
 499             *(pList[globalIndex]+2) = *(pList[globalIndex]+1);
 500             *(pList[globalIndex]+1) = label;
 501
 502             *(pList[globalIndex]+8) = *(pList[globalIndex]+7);
 503             *(pList[globalIndex]+7) = idhit;
 504           }
 505           else{
 506             *(pList[globalIndex]+5) = signal;
 507             *(pList[globalIndex]+2) = label;
 508             *(pList[globalIndex]+8) = idhit;
 509           }
 510         }
 511     } // end of loop pixels in x
 512   } // end of loop over pixels in z
 513
 514
 515 }
 516
 517
 518 //---------------------------------------------
 519 void AliITSsimulationSPD::ChargeToSignal(Float_t **pList)
 520 {
 521   // add noise and electronics, perform the zero suppression and add the
 522   // digit to the list
 523
 524   AliITS *aliITS = (AliITS*)gAlice->GetModule("ITS");
 525
 526
 527   Float_t threshold = (float)fResponse->MinVal();
 528
 529   Int_t digits[3], tracks[3], hits[3],gi,j1;
 530   Float_t charges[3];
 531   Float_t electronics;
 532   Float_t signal,phys;
 533   for(Int_t iz=0;iz<fNPixelsZ;iz++){
 534     for(Int_t ix=0;ix<fNPixelsX;ix++){
 535       electronics = fBaseline + fNoise*gRandom->Gaus();
 536       signal = (float)fMapA2->GetSignal(iz,ix);
 537       signal += electronics;
 538       gi =iz*fNPixelsX+ix; // global index
 539       if (signal > threshold) {
 540          digits[0]=iz;
 541          digits[1]=ix;
 542          digits[2]=1;
 543          for(j1=0;j1<3;j1++){
 544            if (pList[gi]) {
 545              //b.b.          tracks[j1]=-3;
 546              tracks[j1] = (Int_t)(*(pList[gi]+j1));
 547              hits[j1] = (Int_t)(*(pList[gi]+j1+6));
 548            }else {
 549              tracks[j1]=-2; //noise
 550              hits[j1] = -1;
 551            }
 552            charges[j1] = 0;
 553          }
 554
 555          if(tracks[0] == tracks[1] && tracks[0] == tracks[2]) {
 556            tracks[1] = -3;
 557            hits[1] = -1;
 558            tracks[2] = -3;
 559            hits[2] = -1;
 560          }
 561          if(tracks[0] == tracks[1] && tracks[0] != tracks[2]) {
 562            tracks[1] = -3;
 563            hits[1] = -1;
 564          }
 565          if(tracks[0] == tracks[2] && tracks[0] != tracks[1]) {
 566            tracks[2] = -3;
 567            hits[2] = -1;
 568          }
 569          if(tracks[1] == tracks[2] && tracks[0] != tracks[1]) {
 570            tracks[2] = -3;
 571            hits[2] = -1;
 572          }
 573
 574          phys=0;
 575          aliITS->AddSimDigit(0,phys,digits,tracks,hits,charges);
 576       }
 577       if(pList[gi]) delete [] pList[gi];
 578     }
 579   }
 580   delete [] pList;
 581
 582 }
 583
 584
 585 //____________________________________________
 586
 587 void AliITSsimulationSPD::CreateHistograms()
 588 {
 589   // create 1D histograms for tests
 590
 591       printf("SPD - create histograms\n");
 592
 593       fHis=new TObjArray(fNPixelsZ);
 594       for (Int_t i=0;i<fNPixelsZ;i++) {
 595         TString spdName("spd_");
 596            Char_t pixelz[4];
 597            sprintf(pixelz,"%d",i+1);
 598            spdName.Append(pixelz);
 599            (*fHis)[i] = new TH1F(spdName.Data(),"SPD maps",
 600                               fNPixelsX,0.,(Float_t) fNPixelsX);
 601       }
 602 }
 603
 604 //____________________________________________
 605
 606 void AliITSsimulationSPD::ResetHistograms()
 607 {
 608     //
 609     // Reset histograms for this detector
 610     //
 611
 612     for ( int i=0;i<fNPixelsZ;i++ ) {
 613         if ((*fHis)[i])    ((TH1F*)(*fHis)[i])->Reset();
 614     }
 615
 616 }
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